Water filtration, tested, scored and explained
Every recommendation here is scored on a published formula and checked against the manufacturer's own claims. Where those claims cannot be verified, we say so.
Whole house Best whole house water filter systems Scored and ranked, with the right pick for city water and for wells. Guide How do water filters work? The six mechanisms, what each removes, and what each one misses. Guide Do water filters remove fluoride? Carbon removes almost none. Four methods do work — the full comparison. Original research Most water filters are not certified for what they remove We classified the certification language on 93 systems. 68.8% invoke NSF. 21.5% are certified.
Why trust this site
A formula, not a hunch
Every score is calculated from owner ratings, certification, filtration stages and warranty — measured against what is achievable in that category. The weights and benchmarks are published.
See the formula →Our own research
We surveyed the certification language on 93 water filtration systems and found most NSF claims are not certifications. Nobody else has published this.
Read the findings →We say what we do not know
We do not lab-test filters and we do not pretend to. Where a manufacturer claim cannot be verified, the page says so instead of scoring it as confirmed.
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